This comment was posted to reddit on Dec 06, 2018 at 6:15 pm and was deleted within 14 minutes.

There is no nirvana

That's fine, but you can't claim that the Dharma is not philosophical when it makes claims about OBJECTIVE reality. (...)

The difference is that, while Buddhism is all 'bout that Truth yo, its aim is not to state the truth. It's aim is to attain/realize the truth. In fact, as far as the Mahayana goes, ultimately truth is ineffable. But: not unattainable. Conventional truth, such as the truths employed on the path, are, well conventional or relative, or, as one translator from Tibetan provocatively has it, fictional. Truth in the way that it's true that Donald Duck is a white ansiform in naval costume. Patrül Rinpoche said: "Generally speaking, all appearances—from those of the lowest hell of Ultimate Torment up to and including the post-meditationexperience of bodhisattvas on the tenth bhumi—are relative."

Buddhism only concerns itself with the conventional truths of the path, on not for the sake of those truths. In fact, many of the things taught to be true on the path aren't ultimately true, such as impermanence and karma. But they have practical value nonetheless. (Note by the way that I will limit myself to a Mahayana perspective from here on out.)

I've argued with monks about dualism, by the way.

Maybe we're just using the word in different ways. I use dualism to indicate the view that subject and object are ontologically distinct. The Dharma rejects this view. A corollary of that rejection is that the distinction "subjective" vs "objective" makes no sense from the POV of Dharma practice. The Dharma distinguishes valid and invalid relative/conventional perception in stead, where a valid perception functions: when I correctly perceive a cow to be a cow, I will be able to successfully milk her. When I sincerely hallucinate the streetlight in front of my window is a cow, no amount of yanking it will successfully produce milk.

The ultimately empty, but conventionally true perceptions of the path (such as rebirth) are valid because they produce liberated beings (when deployed correctly in practice of course).

Or in other words: the Dharma is not concerned with being objectively true (a concept it philosophically speaking does not recognize), but with being effective in liberating beings. This is what I meant with the cookbook comparison. We're not concerned with the ontology of avocados here, just with making a hella good guac.

Okay, I may have defined it wrongly. Even if nirvana is timeless, the question still remains: how can you "close" the curtains on a window that's supposedly impossible to block?

The sun is not in any meaningful sense blocked by the clouds from the perspective of the sun. Under the clouds it gets pretty dang dark though.

How can pure, free consciousness become clouded, or have the "illusion" of being cloudy? And if it happened once, why can't it happen again, EVEN after the realization of nirvana?

It didn't. We only mistakenly think that it did. Your question makes sense from the deluded perspective that there's a subject that now has this experience, then has that experience and later has another experience. No such subject can be found to exist. Awareness has no natural center. It isn't subject to changing experiences, nor is it static. I am not that consciousness. "I" am just another fleeting experience.

This is why in the Mahayana it is ultimately said that Samsara and Nirvana are inseparable.

Also, avidya may never arise IN THAT SAME UNIVERSE if you truly destroyed all the oranges and all the DNA. However, even doing THAT would not, and could not, stop OTHER universes from coming into existence, creating new planets and new life, and thus, new oranges with all the seeds and DNA arising again. So my point still stands.

From the perspective of an enlightened being nothing actually arises (that only happens from the deluded perception of beings that have themselves not actually ever come into being), nor does anything disappear. The coming and going of universes only exist predicated on ignorance, which itself has never come into being. The samsara/nirvana dichotomy only appears to make sense from a samsaric perspective. (There's a beautiful song by Lama Zhang Yudrakpa about this that I can look up for you if you like.)

And yet: this is why the Buddhas are compassionate. There's countless beings needlessly suffering because they mistakenly think they exist. Pretty horrifying, really.

I say, "All the awareness I see is quite obviously happening from brains." All the evidence points towards brains generating consciousness, and not the other way around.

I have never seen an actual outside-of-experience brain, though. I only have experiences of brains, thoughts of brains, concepts about brains. I have only awarenessy stuff. The materialist supposition is a bit like watching television and coming to the conclusion that there must be actual tiny people in the TV. Like Voltaire (I think) once said about God, I say about a outside-of-awareness (or even awareness-producing) physical reality: I have no need for that supposition.

The empiricist idea seems to go as follows: if on the basis of certain patterns in my experiences I can predict another experience, that experience must be of something "outside". By that line of reasoning I can also draw the conclusion that Smurfs must actually exist, since those cartoon episodes are pretty dang predictable (haven't seen the movies, so I'm not going to speculate on the metaphysics of 3D Smurfs).

And this Buddhist argues (politely and gleefully) right back. I like your thinking. It's spicy! But I suspect you may fundamentally misunderstand what Buddhism is. The Sutras, Tantras and Shastras are much more like cookbooks than they are like European-style scientific or philosophical treatises.

Lol! Spicy? Was something lost in translation there? Either way, I like your adjective:)
I'm fine with admitting if I was mistaken. But Buddhism does NOT just talk about subjectivity and "cookbook-like" aphorisms. It makes claims about OBJECTIVE reality. And when we test those claims, we find them to be lacking. That's the feel I've been getting from contemporary Theravada tradition. Am I mistaken?

As to your final point, that you don't want to accept anything on faith. Have you ever had 100% indubitable certainty about anything?

I agree with you, but I don't need ABSOLUTE certainty. I just need MAXIMAL certainty based on OBJECTIVE EVIDENCE. Just like science. Science doesn't PROVE anything 100%. But it says, "This is the BEST POSSIBLE ANSWER based on our current understanding."

The difference is, with science, I can OBJECTIVELY VERIFY the evidence, share it with others, and come to conclusions that we all can agree on. But SUBJECTIVE phenomenon, by their very nature, can't be used as evidence for OBJECTIVE reality. That's the difference, I feel, between Buddhism and science/skepticism.

Enjoy your dream (within a dream, lol). Goodnight!

P.S.
If you want to talk further, may I PM you? I have some questions for you. We can discuss more in private. Thanks.